Wireless Local Area Network (WLAN) technology includes the well-known IEEE 802.11 family of standards (commonly known as Wi-Fi). Wi-Fi uses 2.4 GHz, and more recently 5 GHz, radio frequency bands to allow two Wi-Fi devices to communicate wirelessly with one another.
Wi-Fi network nodes use a contention based protocol to provide shared and fair access to each channel in the frequency bands. A well-known contention based protocol is Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). In this protocol, a first node sends a data packet to a second node by first sensing a channel to determine if it is idle or not. This is known as a Carrier Sense, CS. If it is determined that the medium is idle, then a transmission attempt may occur. If the medium is not idle, then the first node concludes that the particular channel is busy. The first node may then attempt to transmit on this channel once it has returned to an idle state and a random delay (known as a back-off timer) has elapsed.
Another communications technology, known as small cells (or femtocells, picocells, metrocells or microcells, depending on their coverage areas), has grown in popularity in recent years. These small cells provide cellular communications over a coverage area which is typically much smaller than the traditional macrocell, and is thus suitable to provide cellular coverage within the customer's premises. However, at least one implementation of small cell technology, such as the Long-Term Evolution (LTE) evolved Node B (eNodeB) basestation, uses 2.3 GHz and 2.6 GHz frequency bands for communications. The present inventors have realized, through laboratory testing, that communications between two LTE eNodeBs can cause interference on the 2.4 GHz Wi-Fi frequency band. This is due to out-of-band transmissions from the eNodeB causing sufficient noise on the Wi-Fi 2.4 GHz frequency band that a Wi-Fi node determines that the channel is busy during a Carrier Sense operation. The capacity of the Wi-Fi network is thus compromised by the LTE transmissions.
There are a number of techniques to manage collocated Wi-Fi and small cell devices (i.e. either nearby or when located in the same unit). These are typically routing functions which decide on whether to route traffic over Wi-Fi or the small cell depending on, for example, the Quality of Service (QoS) demands of the data being transmitted (e.g. in application/IP layer bonding) or based on predetermined policies (e.g. ANDSF). However, any transmission over the small cell device may, as detailed above, cause sufficient interference on the Wi-Fi frequency band that any Wi-Fi transmission may be inadvertently blocked. One solution to this problem is to only transmit over Wi-Fi or via the small cell at any one time. However, this clearly introduces undesirable limitations in each network's capacity.
It is therefore desirable to alleviate some or all of the above problems.